Portable communication and/or computing devices (“embedded devices”) can often be linked to various networks. For example, both cell phones and notepad computers can be used to browse web sites offered through the Internet and to send text, graphics, audio, and other types of messages. The messages are typically queued and then sent if and when a link is present.
Often, it is desired to send the communications securely through a communication link. However, for devices that are not always connected to a network, the devices might not have the encryption benefit of encryption services offered by the network, and the message may remain queued insecurely on the device.
For example, when a message to be encrypted is composed, the contents of the message are typically stored in system memory. When the user chooses to save the message to the Drafts folder or send the message, the message is written to and stored in the system database until a network connection can be established and the recipients' public keys can be retrieved to properly encrypt and send the message. Because the system database is open to any application to read or modify, the contents can be subject to a malicious application that might intercept and alter the contents unbeknownst to the sender